The invention relates to a clasp-like sheet metal nut which is suitable for automatic fitting onto a support plate by means of a fitting head which can be brought up to the fastening point. These sheet metal nuts are used in the automobile industry as well as in the household appliances industry and other branches of industry, in order to screw components in plate form to other components. For this purpose, the sheet metal nut is pushed onto the edge of a support plate provided with a hole, until threaded hole and plate hole coincide.
U.S. Pat. No. 4,793,753 discloses such a sheet metal nut which has, for the purpose of automatic fitting, guide lugs formed on the two side edges of the threaded leg at right angles to the plane of the leg, the upper edges of which guide lugs project at least beyond the thread profile and the mutually parallel surfaces of which guide lugs have the same spacing from each other as the side edges of the clasp leg. Thanks to the guide lugs, this sheet metal nut can be conveyed without any problems through a flexible guide channel of rectangular cross section even over considerable distances and guided reliably into the retaining head of a fitting apparatus, likewise known from this publication, the cross-piece between the two legs offering the necessary air impingement surface for the compressed-air conveyance in the guide channel. This known sheet metal nut has proved very successful in conjunction with the associated fitting apparatus wherever the retaining head of the fitting apparatus can be brought freely and unhindered up to the edge of the support plate.
However, in motor vehicle construction, for example on dashboards or other complicated housing walls, there are fastening points which do not lie at the edge of the support plate but in the middle of it, the fastening hole having in front of it a rectangular clearance for inserting the clasp-like sheet metal nut. This clearance is usually just big enough for the sheet metal nut to be introduced with the hanging clasp leg into the clearance obliquely from above and then pushed underneath the edge of the plate.